I guess you didnt get the memo that if the answer to a question you ask has ever been posted before in the history of the interweb you should have searched for it, therefor not having to ask? :lol: (end sarcasm :twisted: )
You want weaver rings, 3/8" mounts are different (weaver mounts are 7/8")
Yes the gun will come with the weaver mount, you supply the (weaver) rings and scope. optics dont need to be weaver compatible, but the rings do, unless you get a re-dot with built in weaver mount....
Can you just add iron sights? No. There is no front sight on the gun.
It would be technically possible to add iron sights, but if you have to ask if its possible, you dont have the equipment or skills to do it, and the cost to have someone do it for you would likley be more than the cost of the gun.
I have seen flash hider/front sight combos for other rifles (mini 14, for one), but never one for a 10/22... it may exist but i dont know.